Merkley has generally been regarded as being in strong position for re-election, in part because Oregon has not elected a Republican in a statewide race since 2002 (when Sen. Gordon Smith won re-election; Merkley defeated Smith in 2008).

The new poll didn't include any head-to-head matchups with Merkley's Republican rivals, who include state Rep. Jason Conger of Bend and Portland pediatric neurosurgeon Monica Wehby.

Democrats were quick to point out that the poll seemed to be skewed toward voters who had supported Republican Mitt Romney in the presidential race and that it avoided any head-to-head matchups, which could show Merkley in a stronger position.

Merkley aide Matt McNally released a statement saying that the senator is "concentrated on doing the job Oregonians elected him to do," and he cited the senator's work on such things as trying to protect consumers, promote good-paying jobs and improve college affordability.

"Although the election is still eleven months away and a Republican opponent has not yet been chosen, the incumbent obviously has some repair work to do with the electorate," said Magellan principal John Diez in a release accompanying the poll.

The poll raises questions about whether it is capturing an accurate snapshot of the electorate. The partisan split in the poll seemed to capture the state's demographics, but 49 percent of respondents say they voted for Romney in the last presidential race while 43 percent voted for President Barack Obama.

Obama won Oregon, 54 percent to 42 percent. While the electorate for the off-presidential year in 2014 will likely be less Democratic, this poll seems to signal a much bigger shift than is likely to occur. It is also possible that, as Obama's approval rating drops, voters are less likely to tell a pollster now that they voted for him a year ago.